2.基因的自由组合定律发生于下图中哪个过程 ( )
AaBb1AB∶1Ab∶1aB∶1ab雌雄配子随机结合子代9种基因型4种表现型
A.① B.② C.③ D.④
解析:基因的自由组合定律的实质是在减数分裂过程中,非同源染色体上的非等位基因随着非同源染色体的组合而自由组合。
答案:A
1.(2009·宁夏高考)已知某闭花受粉植物高茎对矮茎为显性,红花对白花为显性,两对性状独立遗传。用纯合的高茎红花与矮茎白花杂交,F1自交,播种所有的F2,假定所有F2植株都能成活,F2植株开花时,拔掉所有的白花植株,假定剩余的每株F2植株自交收获的种子数量相等,且F3的表现型符合遗传的基本定律。从理论上讲F3中表现白花植株的比例为 ( )
A.1/4 B.1/6 C.1/8 D.1/16
解析:设红花由B基因控制,白花由b基因控制,F1基因型为Bb,F1自交得到F2,拔除白花植株后,F2红花植株的基因型为1/3BB和2/3Bb,F2自交得到F3,只有基因型为Bb的植株自交能产生白花植株,因此理论上讲F3中白花植株的比例为2/3×1/4=1/6。
答案:B
5.Seeing that the thief ________ a bus,the policeman stopped a taxi and ________ it.(get on/get into)
答案:1.abandoned 2.products/produce 3.trained 4.shot 5.got on;got into
4.He was ________ in the back while he was trying to escape.(shoot)
3.These dogs are ________ to look for drugs.(train)
2.Luckily,they finally found new markets for their ________(produce)
1.After his failure in the examination last week,he ________ himself completely to drinking.(abandon)
15.Stand here at the top of the tower and you can get a good ________.
A.sight B.scene C.view D.look
解析:本题考查名词词义辨析。view除了表示“观点,看法;风光,景色;视野,眼界”等意思之外,还可以表示“看,眺望”的意义。如:If you stand here you’ll get a better view of the city.如果你站在这儿,你可以更清楚地看到这个城市。
答案:C
14.________ be given the prize?
A.Who do you suggest B.Who do you suggest that should
C.Do you suggest who should D.Do you suggest whom should
解析:do you suggest在句中用作插入语,特殊疑问词应放在句首,后跟陈述语序可排除C、D。而B项多了that。
答案:A
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